Hollow Mandrel Plugging Tool for Single-Trip Well Abandonment
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Solution Overview
Problem
Current well abandonment methods are time-consuming, labor-intensive, and expensive, often requiring multiple trips into the well and using expensive drilling rigs, and they struggle with ensuring proper cement seals due to poor placement and quality, leading to potential leaks and integrity issues.
Innovation Solution
A plugging tool combining a depth correlation device, a heater, and a perforating tool within a hollow mandrel, allowing a single run to perforate, melt thermally activated material, and form a plug, with a logging tool verifying the seal without damaging the plug.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional cement plugging methods are used, then the well can be abandoned, but the process is time-consuming, labor-intensive, and expensive requiring multiple trips and drilling rigs
Solution Approach 1:
The patent combines multiple operations (perforation, material delivery, melting, and plug formation) into a single integrated tool string that can be deployed in one trip. The heater, material carrier, and delivery mechanism are merged into one device that performs all functions sequentially during a single well intervention operation.
Solution Approach 2:
The plugging material is pre-loaded into the carrier device before deployment. The heater is pre-positioned within the tool string, and all components are prepared in advance so that when the tool is deployed, the plugging process can proceed immediately without requiring separate trips for material delivery or equipment setup.
2Reliability
If cement is used to seal the annulus, then isolation is attempted, but cement quality is difficult to ensure leading to poor placement, micro annuli, and potential leaks
Solution Approach 1:
The invention changes the physical state of the plugging material from solid to liquid through controlled heating. The material is melted to a liquid state for easy flow and distribution into the annulus, then allowed to cool and solidify into a reliable seal. This phase change enables more consistent and complete annulus filling compared to traditional cement placement.
Solution Approach 2:
The patent replaces the chemical-based cement setting process with a thermal-based plugging process. Instead of relying on cement chemistry and setting time, the system uses controlled heating to melt the material and thermal cooling to solidify it, providing more predictable and controllable plug formation.
3Measurement precision
If a logging tool is used to verify plug integrity, then seal quality can be checked, but drilling a hole into the plug is difficult and may compromise plug integrity
Solution Approach 1:
The carrier device is designed with a predetermined hollow cavity that is formed before the plugging operation. This cavity serves as a pre-prepared access path that eliminates the need to drill into the solidified plug later. The cavity is created as part of the material carrier structure, so when the material is delivered and solidifies, the access path already exists.
Solution Approach 2:
The hollow cavity in the carrier device acts as an intermediary structure that provides access to the plug interior without requiring post-installation drilling. This pre-formed cavity serves as a mediator between the external logging tools and the plug material, allowing verification while preserving plug integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient well plugging in a single trip, reducing costs by eliminating the need for drilling rigs and ensuring reliable seals through a single run, with the ability to verify plug integrity using the hollow mandrel for logging tools.
Implementation Method 1
a carrier having placed on its outer side a material with a melting point lower than that of the wellbore... Inside the carrier is a heater... As the heater melts the material on the outside of the carrier, it melts and runs down to the skirt where it cools and solidifies
Implementation Method 2
it melts and runs down to the skirt where it cools and solidifies. As material builds up on the skirt it will seal the wellbore and form a plug
Data Source
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AI summary
A method and apparatus for sealing a well conduit includes moving a plugging tool (21) to a first position in the well conduit, the plugging tool (21) comprising a perforating tool (12) and a hollow mandrel (8) with a heater (8) inside and a meltable material on the outside. The perforating tool (12) is actuated to create openings in the well conduit. The heater (8) is operated to melt or activate the material disposed on an exterior of the mandrel (9). The melted material is allowed to solidify in the conduit to form a plug and to flow into the openings to fill a cross-section of an annular space outside the conduit. A logging tool (2) may thereafter be inserted into the hollow mandrel (9) to check the integrity of the plug.